The present invention relates to a coffee grinding apparatus which produces a selected weight of ground coffee and includes a calibration circuit to calibrate the grinder to accurately produce the selected weight of ground coffee.
A variety of coffee grinding apparatus are available which weigh a quantity of whole coffee beans to be ground or which measure a desired quantity of whole coffee beans as a function of time. For example, Nidiffer U.S. Pat. No. 4,971,259, issued Nov. 20, 1990 shows a coffee grinding apparatus in which beans are retained in a hopper in a gravity feed relationship with a grinding mechanism. Whole beans are dispensed from the hoppers by opening a dispenser or slide gate thereby allowing the beans to fall from the hopper into the grinder. The dispenser is operated for a period of time to allow a selected quantity of beans to fall from the hopper into the grinder. A user operates the grinding apparatus by selecting a grinding time from a reference chart which time corresponds to the grinding time for a desired weight of ground coffee at a desired grinding setting.
Prior art grinding apparatus are quite useful in grinding coffee. Such apparatus measure the coffee to be ground as a function of time by opening the slide gate or dispenser for a selected period of time. While the weight of the ground coffee is rather consistent, the actual weight ground by the apparatus may vary from the values on the reference chart due to characteristics of the beans and the fineness of the grind. For instance, dark roast beans are lower in density than regular roast and produce less weight than regular coffees for a given time setting. In other words, while the reference chart may be highly accurate for a particular bean or for a sample population of beans, a type of bean other than the bean used to calculate the chart may be result in a weight of ground coffee deviating from the desired weight.
Coffee merchants who sell brewed coffee as well as ground coffee tend to make every effort to ensure predictably consistent coffee flavor produced from their ground coffee. This predictable consistency of the brewed beverage is achieved by accurately grinding a selected weight of ground coffee. Since prior art grinding apparatus do not hold some of the parameters constant, for example the characteristics of the bean, the actual weight of ground coffee produced by these grinding apparatus may deviate from the selected ground weight.
It would be desirable to provide a coffee grinding apparatus which consistently grinds a selected weight of ground coffee. To this end, it would be desirable to provide a coffee grinding apparatus which incorporates the ability to calibrate the grinding apparatus.